The principal objectives of this research are: 1. to provide the four possible stable enantiomers of 1,2-dimethyl-3-phenyl-5-diethylcarboxamido-1,2,5,6-tetrahydropyridine and 2. to examine both the racemate and these enantiomers as possible antagonists to LSD and other hallucinogens which possess an indole moiety. Because of the potential importance of these enantiomeric structural analogs of LSD as potential antagonists to the central actions of drugs of abuse and as pharmacological tools in the study of the mode of action of hallucinogens containing an indole moiety, this group of unique compounds will be examined by means of techniques currently ongoing for ascertaining psychopharmacological and biochemical actions. Since this set of enantiomers is a new synthetic entity, any unusual properties, such as antagonism, will be investigated in as much detail as our methodology will permit.